I have always wondered about this and it may be a stupid question but here goes.

Why when you start up a Mustang even at full operating temperature does it have to rev to 2K or so then slowly settle down? My 03 does this. My Moms 06 does this and the 5 liter appears to be the same. I read somewhere it has to do with heating up the cats quicker to lesson emissions. It annoys the hell out of me. Im pretty sure the new 3.7 does this as well no?

Now, my 96 goverment motors truck does not do this nor does it have the hanging rpm issue my Mach 1 does. Its quite civil and programed way better imo. It responds like a carbed car for the most part only better.

Can one of you gurus give me an explanation for this? Thanks.

 

Don't know why they have to do it but they all do.

I have the fix for your Mach 1...

 

Thank you. I am aware of the restrictor plate. Im pieved that Ford thinks this is ok when imo its not. IM not fussing at you at all.

It just bothers me. I wonder if a tune could correct it?

 

I tried tuning and never got it to act like I wanted. There is a "Throttle Decay" that can be adjusted in the tune but never could get it to do what I wanted.

The restrictor plate really makes it drive like it should, instant rpm drop on throttle lift. Only negative is that it restricts the cold idle too so when the air temps are low you sometimes have to keep your foot on the throttle for a minute in the morning.

Used to drive me nuts when I would exit the freeway and lift off the throttle and the car would just keep going for a while as if I still had my foot in it. And it made it difficult for me to shift it smoothly.

I make my restrictor plates out of aluminum, not just gasket material like some of them you see on ebay.

 

My V-6 just goes to around 1200 r.p.m., then to normal idle. I think your right about it having something to do with emissions.

 

You would think also that revving to 2K rpm instantly would not be good for the engine in ultra cold weather. Im sure they have their reasons for this. Ltgndrvr, I know what you mean about lifting off the throttle and the car keeps going for a bit before it reacts. It drives me crazy too.